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4c6de856 CH |
1 | /* |
2 | * Generic binary BCH encoding/decoding library | |
3 | * | |
5b8031cc | 4 | * SPDX-License-Identifier: GPL-2.0 |
4c6de856 CH |
5 | * |
6 | * Copyright © 2011 Parrot S.A. | |
7 | * | |
8 | * Author: Ivan Djelic <ivan.djelic@parrot.com> | |
9 | * | |
10 | * Description: | |
11 | * | |
12 | * This library provides runtime configurable encoding/decoding of binary | |
13 | * Bose-Chaudhuri-Hocquenghem (BCH) codes. | |
14 | */ | |
15 | #ifndef _BCH_H | |
16 | #define _BCH_H | |
17 | ||
18 | #include <linux/types.h> | |
19 | ||
20 | /** | |
21 | * struct bch_control - BCH control structure | |
22 | * @m: Galois field order | |
23 | * @n: maximum codeword size in bits (= 2^m-1) | |
24 | * @t: error correction capability in bits | |
25 | * @ecc_bits: ecc exact size in bits, i.e. generator polynomial degree (<=m*t) | |
26 | * @ecc_bytes: ecc max size (m*t bits) in bytes | |
27 | * @a_pow_tab: Galois field GF(2^m) exponentiation lookup table | |
28 | * @a_log_tab: Galois field GF(2^m) log lookup table | |
29 | * @mod8_tab: remainder generator polynomial lookup tables | |
30 | * @ecc_buf: ecc parity words buffer | |
31 | * @ecc_buf2: ecc parity words buffer | |
32 | * @xi_tab: GF(2^m) base for solving degree 2 polynomial roots | |
33 | * @syn: syndrome buffer | |
34 | * @cache: log-based polynomial representation buffer | |
35 | * @elp: error locator polynomial | |
36 | * @poly_2t: temporary polynomials of degree 2t | |
37 | */ | |
38 | struct bch_control { | |
39 | unsigned int m; | |
40 | unsigned int n; | |
41 | unsigned int t; | |
42 | unsigned int ecc_bits; | |
43 | unsigned int ecc_bytes; | |
44 | /* private: */ | |
45 | uint16_t *a_pow_tab; | |
46 | uint16_t *a_log_tab; | |
47 | uint32_t *mod8_tab; | |
48 | uint32_t *ecc_buf; | |
49 | uint32_t *ecc_buf2; | |
50 | unsigned int *xi_tab; | |
51 | unsigned int *syn; | |
52 | int *cache; | |
53 | struct gf_poly *elp; | |
54 | struct gf_poly *poly_2t[4]; | |
55 | }; | |
56 | ||
57 | struct bch_control *init_bch(int m, int t, unsigned int prim_poly); | |
58 | ||
59 | void free_bch(struct bch_control *bch); | |
60 | ||
61 | void encode_bch(struct bch_control *bch, const uint8_t *data, | |
62 | unsigned int len, uint8_t *ecc); | |
63 | ||
64 | int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len, | |
65 | const uint8_t *recv_ecc, const uint8_t *calc_ecc, | |
66 | const unsigned int *syn, unsigned int *errloc); | |
67 | ||
68 | #endif /* _BCH_H */ |